Writing pen with a base



FIG. 1 is a front view of the writing pen with a base showing my new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a side view thereof;

FIG. 4 is a top view thereof; and,

FIG. 5 is a bottom view thereof. 

The ornamental design for a writing pen with a base, as shown. 